2014-12-25 Created By BaoXinjian
一、摘要
在ORACLE数据库应用调优中，一个SQL的执行次数/频率也是常常需要关注的，因为某个SQL执行太频繁，要么是由于应用设计有缺陷，需要在业务逻辑上做出优化处理，要么是业务特殊性所导致。
如果执行频繁的SQL，往往容易遭遇一些并发性的问题。
那么如何查看ORACLE数据库某个SQL的执行频率/次数，潇湘隐者同学整理如下，借花献佛了 :)
方法1： 通过查询V$SQLAREA或V$SQL的EXECUTIONS来查看SQL的执行次数;
方法2：通过DBA_HIST_SQLSTAT关联DBA_HIST_SNAPSHOT找出某些SQL的执行次数;
方法3：AWR报告查看某个SQL的执行次数;
二、三种方法解析
1. 通过查询V$SQLAREA或V$SQL的EXECUTIONS来查看SQL的执行次数
(1). 缺点
但是这个值的有效性需要结合FIRST_LOAD_TIME来判断，因为V$SQLAREA或V$SQL中不保存历史数据，
具有一定的时效性，所以如果要查询很久以前的某个SQL执行次数是办不到的。
(2). 关于V$SQLAREA 栏位介绍
FIRST_LOAD_TIME VARCHAR2(19) Timestamp of the parent creation time
EXECUTIONS NUMBER Total number of executions, totalled over all the child cursors
(3). 如何查询
SELECT SQL_ID, SQL_TEXT,FIRST_LOAD_TIME, EXECUTIONS
FROM V$SQLAREA
WHERE SQL_ID = '497wh6n7hu14f'
(4). 总结
如果此时清空共享池，那么你会发现V$SQLAREA中对应的SQL的EXECUTIONS次数清零了。
如果要查看某个时间段该SQL语句执行了多少次，那么必须在这两个时间段执行上面SQL语句，两次EXECUTIONS的差值表示这段时间内SQL语句的执行次数。
EXECUTIONS是全局的，往往不能查看某个会话或用户执行了多少次。这也是其局限性之一。
2. 通过DBA_HIST_SQLSTAT关联DBA_HIST_SNAPSHOT找出某些SQL的执行次数。
(1). 缺点
但是部分快照如果没有捕获到有些SQL。这样也就无法通过下面SQL语句查看执行次数。
也是就说这种方法是有缺陷的。执行越频繁的语句，也越容易被SNAPSHOT抓取到.
(2). 执行语法
SELECT M.SQL_ID,
TO_CHAR (N.BEGIN_INTERVAL_TIME, 'YYYY-MM-DD') "DATETIME",
SUM (M.EXECUTIONS_DELTA) EXECUTIONS
FROM DBA_HIST_SQLSTAT M, DBA_HIST_SNAPSHOT N
WHERE M.SNAP_ID = N.SNAP_ID
AND M.DBID = N.DBID
AND M.INSTANCE_NUMBER = N.INSTANCE_NUMBER
AND M.INSTANCE_NUMBER = 1
AND TO_CHAR (N.BEGIN_INTERVAL_TIME, 'YYYY-MM-DD') = '2014-12-25'
AND M.SQL_ID = '497wh6n7hu14f'
GROUP BY M.SQL_ID, TO_CHAR (N.BEGIN_INTERVAL_TIME, 'YYYY-MM-DD')
ORDER BY M.SQL_ID
3. AWR报告查看某个SQL的执行次数，同上面一样，AWR报告也受SNAPSHOT影响。不一定捕获了你需要查询的SQL
4. 查看当前数据库执行次数最多的SQL，例如，查询执行最频繁的TOP 15的SQL语句。
SELECT SQL_TEXT, EXECUTIONS
FROM (SELECT SQL_TEXT,
EXECUTIONS,
RANK () OVER (ORDER BY EXECUTIONS DESC) EXEC_RANK
FROM V$SQLAREA)
WHERE EXEC_RANK <= 15;
5. 查看执行SQL的历史记录信息
SELECT DBMS_LOB.SUBSTR (sql_text, 100, 1) SQL_SHORT, tab1.sql_id, DBMS_LOB.getlength (sql_text) SQL_Len, ROUND (TOTAL_WAIT / 1000000, 2) TOTAL_WAIT_SECS, ROUND (ELAPSED_TIME_DELTA / 1000000, 2) TOTAL_TIME_SECS, TO_CHAR (BEGIN_INTERVAL_TIME, 'DAY', 'NLS_DATE_LANGUAGE=AMERICAN') Week_Day, BEGIN_INTERVAL_TIME, END_INTERVAL_TIME, EXEC_COUNT, AVG_CPU_TIME_SECS, AVG_ELAPSED_SECS, ROUND (ELAPSED_TIME_DELTA / 1000000, 0) ELAPSED_TIME_DELTA, ROUND (AVG_ROWS_PROCESSED, 1) AVG_ROWS_PROCESSED, PLAN_HASH_VALUE, MODULE, ACTION, PARSING_SCHEMA_NAME, (SELECT username FROM dba_users WHERE user_id = PARSING_USER_ID) PARSING_USER, AVG_BUFFER_GETS, AVG_DISK_READS, AVG_IOWAIT AVG_iowai_secs, AVG_CCWAIT AVG_ccwait_secs, AVG_CLWAIT AVG_clwait_secs, AVG_APWAIT AVG_apwait_secs, AVG_PX_SERVERS, AVG_PARSE_CALLS, tab1.SNAP_ID, tab1.INSTANCE_NUMBER, AVG_CELL_UNCOMPRESSED_BYTES, AVG_DIRECT_WRITES, AVG_IO_INTERCONNECT_BYTES, AVG_IO_OFFLOAD_ELIG_BYTES, AVG_IO_OFFLOAD_RETURN_BYTES, AVG_JAVEXEC_TIME, AVG_OPTIMIZED_PHYSICAL_READS, AVG_PLSEXEC_TIME_DELTA, AVG_SORTS_DELTA, -- BIND_DATA, -- -- (Falta arreglar) listagg( (select * from table(dbms_sqltune.extract_binds(bind_data)), '#') WITHIN GROUP (ORDER BY 1)) Binds , DBMS_LOB.SUBSTR (sql_text, 2000, 1) SQL_TEXT1, DBMS_LOB.SUBSTR (sql_text, 2000, 2001) SQL_TEXT2, DBMS_LOB.SUBSTR (sql_text, 2000, 4001) SQL_TEXT3, DBMS_LOB.SUBSTR (sql_text, 2000, 6001) SQL_TEXT4, DBMS_LOB.SUBSTR (sql_text, 2000, 8001) SQL_TEXT5, DBMS_LOB.SUBSTR (sql_text, 2000, 10001) SQL_TEXT6, DBMS_LOB.SUBSTR (sql_text, 2000, 12001) SQL_TEXT7, DBMS_LOB.SUBSTR (sql_text, 2000, 14001) SQL_TEXT8, DBMS_LOB.SUBSTR (sql_text, 2000, 16001) SQL_TEXT9, DBMS_LOB.SUBSTR (sql_text, 2000, 18001) SQL_TEXT10 FROM DBA_HIST_SQLTEXT D, DBA_HIST_SNAPSHOT N, ( SELECT S.SQL_ID SQL_ID, instance_number, SUM (EXECUTIONS) EXEC_COUNT, ROUND ( (SUM (CPU_TIME_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) AVG_CPU_TIME_SECS, ROUND ( (SUM (ELAPSED_TIME_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) AVG_ELAPSED_SECS, SUM (ELAPSED_TIME_DELTA) ELAPSED_TIME_DELTA, ROUND ( (SUM (ROWS_PROCESSED_DELTA) / SUM (EXECUTIONS)), 4) AVG_ROWS_PROCESSED, PLAN_HASH_VALUE, MODULE, ACTION, PARSING_SCHEMA_NAME, PARSING_USER_ID, ROUND (SUM (BUFFER_GETS_DELTA) / SUM (EXECUTIONS), 4) AVG_BUFFER_GETS, ROUND (SUM (DISK_READS_DELTA) / SUM (EXECUTIONS), 0) AVG_DISK_READS, SNAP_ID, ROUND ( (SUM (IOWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) AVG_IOWAIT, ROUND ( (SUM (CCWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) AVG_CCWAIT, ROUND ( (SUM (CLWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) AVG_CLWAIT, ROUND ( (SUM (APWAIT_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) AVG_APWAIT, ROUND (SUM (PX_SERVERS_EXECS_DELTA) / SUM (EXECUTIONS), 4) AVG_PX_SERVERS, ROUND (SUM (PARSE_CALLS_DELTA) / SUM (EXECUTIONS), 4) AVG_PARSE_CALLS, ROUND (SUM (CELL_UNCOMPRESSED_BYTES_DELTA) / SUM (EXECUTIONS), 4) AVG_CELL_UNCOMPRESSED_BYTES, ROUND (SUM (DIRECT_WRITES_DELTA) / SUM (EXECUTIONS), 4) AVG_DIRECT_WRITES, ROUND (SUM (IO_INTERCONNECT_BYTES_DELTA) / SUM (EXECUTIONS), 4) AVG_IO_INTERCONNECT_BYTES, ROUND (SUM (IO_OFFLOAD_ELIG_BYTES_DELTA) / SUM (EXECUTIONS), 4) AVG_IO_OFFLOAD_ELIG_BYTES, ROUND (SUM (IO_OFFLOAD_RETURN_BYTES_DELTA) / SUM (EXECUTIONS), 4) AVG_IO_OFFLOAD_RETURN_BYTES, ROUND (SUM (JAVEXEC_TIME_DELTA) / SUM (EXECUTIONS), 4) AVG_JAVEXEC_TIME, ROUND ( SUM (OPTIMIZED_PHYSICAL_READS_DELTA) / SUM (EXECUTIONS), 4) AVG_OPTIMIZED_PHYSICAL_READS, ROUND (SUM (PLSEXEC_TIME_DELTA) / SUM (EXECUTIONS), 4) AVG_PLSEXEC_TIME_DELTA, ROUND (SUM (SORTS_DELTA) / SUM (EXECUTIONS), 4) AVG_SORTS_DELTA, SUM ( IOWAIT_DELTA + CCWAIT_DELTA + CLWAIT_DELTA + APWAIT_DELTA) TOTAL_WAIT, MAX (BIND_DATA) BIND_DATA FROM (SELECT S.*, DECODE (EXECUTIONs_DELTA, 0, 1, EXECUTIONS_DELTA) EXECUTIONS FROM DBA_HIST_SQLSTAT S) S WHERE 1 = 1 -- and ( PARSING_SCHEMA_NAME like 'EUS%' ) -- Filter by schema name GROUP BY S.SQL_ID, instance_number, S.SNAP_ID, PLAN_HASH_VALUE, MODULE, ACTION, PARSING_SCHEMA_NAME, S.INSTANCE_NUMBER, PARSING_USER_ID HAVING ROUND ( (SUM (ELAPSED_TIME_DELTA) / SUM (EXECUTIONS)) / 1000000, 4) >= 10 -- Filter >= n secs ORDER BY 5 DESC) TAB1 WHERE D.SQL_ID = TAB1.SQL_ID AND TAB1.snap_id = N.snap_id -- and upper(tab1.module) like '%PKG_BATCH_PROCESSES_SDM%' AND d.sql_id IN ('6tmcqrydfgdtc') -- AND D.SQL_ID in ( select distinct sql_id from DBA_HIST_ACTIVE_SESS_HISTORY where top_level_sql_id = '85xkhugz5kt8h' ) -- AND upper(DBMS_LOB.SUBSTR (sql_text, 100, 1)) LIKE 'INSERT%' -- AND upper(DBMS_LOB.SUBSTR (sql_text, 1000, 1)) LIKE 'SELECT%' -- AND upper(DBMS_LOB.SUBSTR (sql_text, 3000, 1)) LIKE '%INACTIVE%' AND BEGIN_INTERVAL_TIME > SYSDATE - 60 -- and BEGIN_INTERVAL_TIME between to_date('05/09/2013 07:50:00', 'DD/MM/YYYY hh24:mi:ss') AND to_date('05/09/2013 16:10:00', 'DD/MM/YYYY hh24:mi:ss') -- and BEGIN_INTERVAL_TIME >= (SELECT job_start_datetime - (2/24) FROM job_status WHERE job_name = 'RAVLDBSK' AND cob_date = (SELECT current_cob_date FROM eus_cob)) -- and BEGIN_INTERVAL_TIME <= (SELECT job_end_datetime + (2/24) FROM job_status WHERE job_name = 'RAVLDBSK' AND cob_date = (SELECT current_cob_date FROM eus_cob)) -- order by AVG_ELAPSED_SECS DESC -- order by ELAPSED_TIME_DELTA DESC ORDER BY BEGIN_INTERVAL_TIME DESC -- order by TOTAL_WAIT_SECS desc；
Thanks and Regards
部分参考：潇湘隐者 - http://www.cnblogs.com/kerrycode/p/4111746.html
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